소성∙가공 (Transactions of Materials Processing)

  • 제20권4호
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  • Pages.309-315
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  • 2011
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  • 1225-696X(pISSN)
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  • 2287-6359(eISSN)
한국소성∙가공학회 (The Korean Society for Technology of Plasticity and materials processing)
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SPRC440 강판재의 미세조직 구성이 동적 인장 특성에 미치는 영향

Effect of Microstructure on Dynamic Tensile Characteristics of SPRC440 Sheet

  • 이성희 (부산대학교 재료공학과) ;
  • 임영목 (재료평가연구그룹) ;
  • 이정환 (한국기계연구원 부설 재료연구소) ;
  • 김인배 (한국기계연구원 부설 재료연구소) ;
  • 김양도 (한국기계연구원 부설 재료연구소)
  • 투고 : 2011.04.14
  • 심사 : 2011.05.27
  • 발행 : 2011.07.01
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초록

The behavior of metallic materials at high strain rates shows different characteristics from those in quasi-static deformation. Therefore, the strain rate should be considered when simulating crash events. The objective of this paper is to evaluate the dynamic tensile characteristics of SPRC440 as a function of the volume fraction of phases. As-received SPRC440 is composed of ferrite and pearlite phases. However, ferrite and martensite phases were observed after heat treatment at $730^{\circ}C$ and $780^{\circ}C$ for 5 minutes, as expected by calculations based on the curves from dilatometry tests. High cross-head speed tensile tests were performed to acquire strain-stress curves at various strain rates ranging from 0.001 to $300\;s^{-1}$, which are typical in real vehicle crashes. It was observed that the flow stress increases with the strain rate and this trend was more pronounced in the as-received specimens consisting of ferrite and pearlite phases. It is speculated that the dislocation density in each phase has an influence on the strain rate sensitivity.

키워드

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